Torque control device for a potential-energy torque-generating mechanism

ABSTRACT

A device for accurately and sensitively positioning a leverage weight on the lever arm of a torque-generating mechanism of potential-energy type in accordance with radius changes of a roll being wound or unwound. Cable-and-sheave power and return assemblies are attached to a distance measuring means which senses the periphery of the roll and to either end of the leverage weight whereby the torque exerted by the mechanism is selectively controlled. A ratio-change means is also provided so that tension on a fabric being wound or a warp being unwound can be selectively varied in response to changes in radius of the take-up roll or warp beam, respectively.

United States Patent [1 1 Zebley Feb. 19, 197 4 TORQUE CONTROL DEVICE FOR A 1,952,913 3 1934 Dickhaut 242/75.43 POTENTIADENERGY 2,462,558 2/1949 Schevermann 242/75.43

TORQUE-GENERATING MECHANISM Inventor:

Assignee:

Filed:

Appl. N0.: 136,505

Donald Dane Zebley, Greenville, SC.

United Merchants and Manufactures, Inc., New York, NY.

Apr. 22, 1971 References Cited UNITED STATES PATENTS 12/1956 Rush v 242/75.5 7/1934 Roberts 242/75.51

Primary ExaminerGeorge F. Mautz Assistant ExaminerEdward J. McCarthy Attorney, Agent, or Firm-Jules E. Goldberg 5 7 ABSTRACT A device for accurately and sensitively positioning a leverage weight on the lever arm of a torquegenerating mechanism of potential-energy type in accordance with radius changes of a roll being wound or unwound. Cable-and-sheave power and return assemblies are attached to a distance measuring means which senses the periphery of the roll and to either end of the leverage weight whereby the torque exerted by the mechanism is selectively controlled. A ratiochange means is also provided so that tension on a fabric being wound or a warp being unwound can be selectively varied in response to changes in radius of the take-up roll or warp beam, respectively.

27 Claims, 8 Drawing Figures PATENTEDFEBIQIQH 3.792.826

SHEET 1 [IF 4 INVENTDPL 2 m4 DONALD D. ZEBLEY i r .iv 22 MQM D Q BWWM ATTOQN EYS a. E N2 s xamwzu 2N SHEEI U? 4 PATENTED EB 9 9 4 TORQUE CONTROL DEVICE FOR A POTENTIAL-ENERGY TORQUE-GENERATING MECHANISM CROSS-REFERENCE TO RELATED APPLICATIONS This application is related to the following two applications, filed on even date herewith: Take-up Device Having a Tension-Derived Compacting Means, of Donald Dane Zebley, U.S. Ser. No. 136,474 now U. S. Pat. No. 3,707,996 and Joseph W. Cashion and Potential-Energy Torque-Generating Mechanism for Operating a Take-Up Roll, of Donald Dane Zebley, U.S. Ser. No. 136,477 now US. Pat. No. 3,753,452.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to winding and unwinding devices and especially relates to position control of the leverage weight in a torque-generating mechanism of the potential-energy type in accordance with distancevariable torque requirements. It specifically relates to distance-sensitive cable-and-sheave assemblies for automatic positioning of a movable member.

2. Description of the Prior Art In winding and unwinding of relatively slow-moving flexible materials of indeterminate length, electric drives are commonly used to generate torque for winding thereof or to brake the unwinding thereof. However, as the roll being wound or unwound becomes larger, disproportionate amounts of electricity are consumed and equivalent heat is generated. For example in a textile mill, 20 take-up machines roughly require 1 ton of air conditioning to offset their heat output. Furthermore, if a few picks are missed in a loom, an electric-motor powered take-up device therefor cannot be backed-up for fabric repairwithout loss of tension in the fabric and telescoping of the roll being wound. Other disadvantages of electric-motor drive for a takeup device in a textile mill include sudden power demands when a plurality of looms go on the line and sudden increases in tension caused by power surges which may cause the fabric to be pulled through the loom, resulting in missed picks and other defects. In addition, during shut down, as over weekends and holidays, electric power continues to be consumed by electric-motor take-up devices for maintenance of tension on the fabric being woven.

Such woven goods as carpets, pa permakers felts, filter cloth (both wire and textile), tire fabrics, belting, and coarsely woven textiles such as gray goods are particularly in need of a torque-generating mechanism that consumes no energy when quiescent, allows back-up of the connected loom for fabric repairs, and maintains constant tension upon the woven material at all times. The co-pending application, Potential-Energy Torque-Generating Mechanism for Operating a Take- Up Roll", U.S. Ser. No. 136,477, provides such a device.

When constant torque is exerted upon the mandrel or drive shaft of a take-up roll upon which flexible mate rial is being wound or unwound, the tension produced upon the flexible material at the periphery thereof steadily diminishes, if the roll is being wound, or steadily increases, if the roll is being unwound, in proportion to the radius of the roll. Some fabrics need steady diminishment of tension, such as glass cloth which is extremely slippery and winds better if tension output to the periphery of the take-up roll is allowed to decay normally during winding thereof. Other fabrics, particularly heavy and thick materials such as belting need constant tension or application of a specific tensional pattern as the roll increases in diameter. F urthermore, inertia requirements for a large-diameter take-up roll which is in steady communication with a loom becomes significant because a loom typically operates in a succession of very small starts and stops in accordance with movement of the lay.

When tending a leverage-actuated potential-energy torque-generating mechanism, the operator must periodically change the position of the leverage weight along the lever arm if constant tension is needed for the material being wound or if a specific tensional pattern is required therefor. Because of human fallibility and various operating room exigencies, such weight movements are seldom repeated at the same intervals during successive roll build-ups so that no two wound rolls are necessarily closely alike. A means for automatic movement of the weight in response, to growth or shrinkage in diameter of the roll being wound or unwound can relieve the operator of a troublesome duty and impart torque limits that vary accoi ding to a selectible schedule that is reproducible from one roll to the next.

SUMMARY OF THE INVENTION Accordingly, an object of the invention is to provide a distance-sensitive torque-control device that is operable with a potential-energy torque-generating mechanism to move the leverage weight and provide a selected torque-change pattern in response to change in radius of the roll being wound or unwound.

It is a further object of this invention to provide a means for changing the ratio of the response to such change in roll radius.

It is an additional object to provide a torque-control device that is in constant equilibrium and maintains a selected position of a leverage weight upon the lever I arm of a potential-energy torque-generating mechanism at all times in response to the radius measurement of the roll being wound or unwound.

The torque control means of this invention comprises:

l. a distance measuring means for measuring radius changes of a roll being wound or unwound,

2. a distance-transmitting means in the form of a cable-and-sheave power assembly for imparting these radius changes to a slidably attached leverage weight on a lever arm of a potential-energy torque-generating or torque-consuming mechanism which powers or brakes, respectively, the roll being measured, and

3. a tension-maintaining means in the form of a cable-and-sheave return assembly for maintaining the leverage weight in a state of equilibrium.

When a particular pattern of torque response to diameter changes is desired, a ratio-change means is utilized in connecting the cable-and-sheave power assemblyto the distance-measuring means, although the torque-control device of this invention is entirely operable without the ratio-change means. This ratio-change" means comprises chordal shift, pivotable shift, and angular shift attachment arrangements with which the terminal portion of the power assembly is connected to the distance measuring means.

This torque control means is useful for selectively controlling torque generation or torque consumption and simply requires a slightly larger return weight for overcoming friction during unwinding operations as compared to winding operations. In the accompanying drawings, the distance measuring means is shown as a pivotably attached web reversing means in the form of an S-wrap assembly which is described in the copending application, Take-Up Device Having a Tension-Derived Compacting means. However, it is satisfactory as any type of rider roll or traveler roll which rests upon or otherwise contacts the surface of a roll of flexible material being wound or unwound. For use with the ratio-change means, however, the rider roll must be pivotably movable from a remotely located pivot. The cable-and-sheave assembly is suitably constructed of aircraft cable and sheaves, awning sheaves, and like articles as a cable system and a sheave system.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective, diagrammatic view of a takeup roll being wound with fabric, a rider roll in the form of an S-wrap assembly which rests upon the roll of flexible material thereupon, the single-arm leverage means of a torque-generating mechanism of potential-energy type, and the torque-control device of this invention.

FIG. 2 is similar to FIG. 1 except that dual leverage means and dual torque-control devices are shown.

FIG. 3 is a perspective view of the block-insert embodiment of this invention having exposed terminal reaches of the cable.

FIG. 4 is a plan sectional view of the embodiment shown in FIG. 3, taken in the direction of the arrows 44 in FIG. 3.

FIG. 5 is a plan sectional view, similar to FIG. 4, of the block-insert embodiment with enclosed terminal reaches of the cable.

FIG. 6 is'a transverse sectional view of the fully enclosing lever arm taken in the direction of the arrows 6-6 in FIG. 5.

FIGS. 7 and 8 illustrate the means for selectively changing the ratio of the response to change in roll radius as end views of the take-up roll, supporting structure, and S-wrap assembly shown in FIGS. 1 and 2. FIG. 7 shows a bare take-up roll, and FIG. 8 shows a fully wound take-up roll.

DESCRIPTION OF THE BASIC EMBODIMENT The basic embodiment is shown in FIG. 1 in perspective; A take-up roll 91 is rotatably attached to a supporting structure which is not shown except for the fragments 93, 94. A rider assembly 80, shown as an S- wrap assembly which forms no part of the present invention, comprises the swing rod 81 which is attached to the supporting structure, the swing rod journal 82 which is pivotably attached to the swing rod 81, the support arm 83 which is pendantly attached to the swing rod journal 82, the end plate 86 which is pivotably attached to the support arm 83 with a positioning nut 85, and the triad of rolls comprising the reverse roll 87, the spreader roll 88, and the pressure roll 89, each of which is rotatably attached at one end thereof to the end plate 86 shown in FIG. 1 by journals 87a, 88a and 89a, respectively. Because the S-wrap assembly is pivotably resting against the surface of the roll 9! initially and subsequently against the surface of the fabric roll 92, the pressure roll 89 exerts a line-of-contact pressure thereagainst so that any changes in radius of the fabric roll 92 are reflected by corresponding pivoting of the arm 83.

Alongside of and attached to the supporting structure is the leverage means 60, which is described in the copending application, Potential-Energy Torque- Generating Mechanism for Operating a Take-Up Roll", but is no part of the instant invention. The leverage means comprises the pivot shaft 61 which is attached to the supporting structure, the pivot hub 62 which is pivotably attached to the pivot shaft 61, the lever arm 63 which is rigidly and perpendicularly attached to the pivot hub 62, and the leverage weight 64 which is slidably attached to the lever arm 63. As a part of this invention, the end plate is rigidly and perpendicularly attached to the free end of the lever arm 63, the weight plate 66 is rigidly and perpendicularly attached to the leverage weight 64, and the return weight 67 is attached by 'means of a cable-and-sheave assembly to the weight plate 66.

The sheave system, in the cable-and-sheave power assembly and the cable-and-sheave return assembly, comprises the ratio-change sheave 21, the frame sheave 22, the directional-change sheave 23, the axial sheave 24, the lever-arm sheave 25, the leverage sheave 26, and the return sheave 27. Each of these sheaves is attached to the supporting structure in a suitable way to permit rotation in the desired plane with minimum friction. The frame sheave 22, for example, is attached to an extension of the fragment 93 of the supporting structure. The axial sheave 24 must be mounted so that the center of the cable passing thereover intersects, as nearly as possible, the axis of the pivot shaft 61 as clearly shown in FIG. I for the preferred embodiment which is described hereinafter.

The cable system, in the cable-and-sheave power assembly and the cable-and-sheave return assembly, comprises the ratio-change reach 41 which extends from the selected attachment point on the rider assembly to the ratio-change sheave 21, the frame reach 42 which extends therefrom to the frame sheave 22, the transverse reach 43 which extends therefrom to the directional-change sheave 23, the vertical reach 44 which extends therefrom to the axial sheave 24, the lever-arm reach 45 which extends therefrom to the leverarm sheave 25, the arm-plate reach 46 which extends therefrom to the leverage sheave 26, and the leverage reach 47 which extends therefrom to the attachment point 31 on the leverage weight 64. The cable system further comprises the return reach 48 which extends from the attachment point 32 on the weight plate 66 to the return sheave 27 and the suspension reach 49 which extends downwardly therefrom to the point of attachment on the return weight 67.

These cable-and-sheave assemblies are in constant equilibrium and are completely responsive to the smallest changes in position of the distance measuring means,

which is rider assembly 80. When used to control torque changes during the winding of a relatively lightweight fabric, as on a take-up roll connected to a loom, for example, a total weight of 8% pounds as return weight 67 was found to give adequate return force for overcoming friction in the sheave mountings and in sliding of the leverage weight 64 upon the lever arm 63. When this torque control device was used during unwinding, as on a warp let-off to a loom, a weight of 12 pounds as return weight 67 was found to be sufficient for moving the leverage weight 64 inwardly upon the lever arm 63.

The ratio-change means, shown in FIGS. 1, 7, and 8, comprises structure and attachment arrangements whereby the pattern of torque build-up in response to change in roll radius can be selectively altered in accordance with such characteristics of the fabric or warp being wound or unwound, such as delicacy, picks per inch, tensile strength, thickness, weight, etc., according to the operator's judgment and on-the-spot experimentation. The structure comprises the horizontal beam 93 and the rigidly attached stud 94. Other horizontal members, such as the arm 93', may also be selectively attached perpendicularly to the stud 94, so that they project toward the arm 83 in parallel to the beam 93, and be provided with a plurality of positions, such as the position 103, for selectively mounting the ratiochange sheave 21c, similarly to the positions 103 and 104 for the sheave 21a.

The attachment arrangements on the supporting structure and the rider assembly 80 for selectively connecting the terminal reach 41 are shown in FIGS. 7 and 8 as comprising the pivotably disposed points 105, 106, 107, 108, and 109, which are suitably spaced apart on the pivotable arm 83 and may be at any place on the continuum represented by the arm 83. These arrangements further comprise the vertically disposed positions 95, 96, 97, 98 and 99, which are also suitably spaced apart and preferably are correspondingly positioned to the pivotably disposed points so that the sheave position 97 is arcuately aligned with the attachment point 107, for example, whereby the reach 41b is substantially horizontal when the take-up roll 91 is bare. The arrangements further comprise the sheave positions 103 and 104 which are laterally disposed along the beam 93 for mounting the sheave 21a inwardly of the sheave 21 at the extreme position 102.

Attachment of the terminus of the power cable to the point 101 creates the horizontally disposed ratiochange reach 41, between the point 101 and the sheave 21, which is very short as shown in FIG. 7 and becomes considerably longer, as shown in FIG. 8, in direct measurement of the increase in radius of the fabric roll 92 and at all times represents a chord of the pivoting angle described by the pressure roll 89 during build-up of the fabric roll 92. Direct measurement of radius increase is rarely needed. Generally, build-up of fabric tension according to some selected function of the radius increase is required in accordance with fabric characteristics.

Using one of the alternative positions 103 or 104 on the beam 93 for locating the ratio-change sheave 21a creates the chordal-shift attachment arrangement when the terminus of the power cable is attached to the point 101. The reach 410 (which is shown in FIG. 8 only) continues to represent a chord of the pivoting angle as the roll 92 builds up in radius.

Attachment of the terminus of the power cable to one of the pivotably disposed points 105 or 106 creates the angular-shift attachment arrangement with respect to the sheave 21 at the position 102. If the terminus is attached at the point 105 or the point 106, for example, the horizontally disposed reach 41 becomes the angularly disposed reach 41' or 41 respectively, which angularly changes as the fabric roll 92 increases in radius, as in evident from comparing FIGS. 7 and 8. The distance increase which is transmitted to the leverage weight 64 can be calculated as the cosine of the angle formed between the reaches 41 and 41', for example, at any selected moment. This relationship is a function of elapsed time. The rate of change lessens as the sheave 21a is located farther away from the rider assembly 80, as at positions 103 and 104, because the initial ratio-change reach 41a is proportionately longer than the reach 41, when the chordal-shift and angular shift attachment arrangements are combined.

Using one of the vertically disposed positions 95, 96, 97, .98, 99 for the ratio-change sheave creates the pivotable shift arrangement in combination with one of the pivotably aligned points 105, 106, 107, 108, 109 that is horizontally disposed thereto. For example, the sheave 21b is suitably located at the position 97 so that the horizontally disposed reach 41b stretches to the point 107. The pivotably shifted reach 41b is then lessened in length, as compared to the reach 41a between the sheave 21a and the point 101, according to the pivoting radius from the swing rod 81 to the attachment point 107, for example, as compared to the overall pivoting radius of the pressure roll 89. The angularly shifted reaches 41b, 41b" are also lessened in length compared to the reaches 41a, 41a", as seen in FIGS. 7 and 8.

By utilizing one or more of these shift arrangements, alone or in combination, for attaching the terminus of the power cable to the rider assembly 80 and selectively locating the ratio-change sheave, a ratio-change means is created which permits selectively changing tension on a fabric being wound or warp being unwound, respectively. Locating the ratio-change sheave at a position such as at 103', for example, and attaching the cable terminus, which is preferably equipped with an S-hook or snap-hook, to a higher attachment point, such as point 107, is an example of using all three of the shift attachment arrangements provided herein. Building up tight rolls without telescoping for any fabric being wound is much more easily accomplished thereby.

The lever-arm reach 45, the leverage reach 47, and the return reach 48 must be parallel. to the lever arm 63. The axial sheave 24 and the return sheave 27 must be rotatably positioned so that the centers of the cables passing thereover between reaches 44 and 45 and reaches 48 and 49 must intersect the axis of the pivot shaft-61.

DESCRIPTION OF THE DUAL-ARM EMBODIMENT FIG. 2 shows the dual-arm embodiment of the torque-control device of this invention for use on a dual-arm torque-generating mechanism of the potentialenergy type. The torque-control device of FIG. 1 is duplicated with the same numbers thereon as the upper leverage means 60. The lower leverage means is shown therebeneath.

The lower leverage means 70 comprises the pivot shaft 71 which is attached at each end thereof to the supporting structure, the pivot hub 72 which is pivotably attached to the pivot shaft 71, the lever arm 73 which is rigidly and perpendicularly attached to the pivot hub 72, and the leverage weight 74 which is slidably attached to the lever arm 73. As a part of this invention, the end plate 75 is rigidly and perpendicularly attached to the lever arm 73 at the free end thereof, the

weight plate 76 is rigidly and perpendicularly attached to the leverage weight 74, and the return weight 77 is pendantly attached to the terminus of the return cable.

The corresponding cables and sheaves in the power and return sheave-and-cable assemblies for the lower leverage means 70 comprise the ratio-change reach 51 which is attached at the end thereof to the same attachment points 101, 105-109 on the rider roll assembly 80 as the terminus of the reach 41. The power assembly also comprises the frame reach 52 therefrom to the frame sheave 22', the transverse reach 53 therefrom to the sheave 23, the vertical reach 54 therefrom to the axial sheave 34, the lever-arm reach 55 therefrom to the lever-arm sheave 35, the arm reach 56 therefrom to the leverage sheave 36, and the leverage reach 57 therefrom to the attachment point 38 on the leverage weight 74. The return assembly comprises the return reach 58 from the attachment point 39 on the weight plate 76 to the return sheave 37 and the suspension reach 59 therefrom to the return weight 77. The leverarm reach 55, the leverage reach 57, and the return reach 58 must be parallel to the lever arm 73.

The axial sheave 34 and the return sheave 37 must be so positioned that the centers of the cables passing thereover intersect the axis of the pivot shaft 71. The sheaves 23, 23 must be separately rotating sheaves, but the sheaves 22, 22' and the sheaves 21, 21 may be double sheaves.

The dual-arm embodiment is also useful with or without a ratio-change means. In general, if a single fabric is to be wound, for example, over a long period of time, a single chordal, pivotable, or angular shift arrangement, or combination thereof, may be used.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments are shown in FIGS. 3, 4, 5, and 6. The embodiment shown in FIGS. and 6, having enclosed terminal reaches, is merely a slight variation on the embodiment shown in FIGS. 3 and 4 and is hereinafter discussed as closely related thereto.

FIG. 3 shows the leverage means 160 with a cable system passing through the center of the pivot shaft 161, 161'. This embodiment is similar to the basic embodiment shown in FIG. 1, in that a single lever arm is used.

The leverage means 160 in this preferred embodiment comprises the two-part pivot shaft 161, 161', the pivot hub 162 which is journaled at each end thereof to each part of the pivot shaft 161, 161', the lever arm 163 which is rigidly and perpendicularly attached to the pivot hub 162, and the leverage weight 164 which is slidably attached to the lever arm 163. As a part of this invention, the return weight 167 is pendantly attached to the terminus of the return cable system, the sheave box 168 is inserted into the pivot hub 162 through a slot at the side thereof, opposite to the lever arm 163 and between the pivot bearings 169,. 169 by means of which the pivot hub 162 is journaled on both parts of the pivot shaft 161, 161, as shown in FIG. 4. The parts of the pivot shaft 161, 161 are rigidly attached to the supporting structure 193, 194.

The cable system begins with the ratio-change reach 141 which passes under the ratio-change sheave 121, becomes the frame reach 142 therefrom to the frame sheave 122, passes upwardly as the vertical reach 144 to the axial sheave 124, becomes the transverse reach 143 in the center of the pivot shaft 161 therefrom to the lever-arm sheave I25, and then passes therefrom through the interior of the lever arm 163 as the leverarm reach 145 to the leverage sheave 126, and thence passes outwardly of the lever arm 163 as the leverage reach 147 to the attachment point 131 on the leverage weight 164. The axial sheave 124 is rotatably disposed at the end of the extended pivot shaft 161 so that the center of the cable passing thereover coincides with the axis of the pivot shaft 161.

The cable-and-sheave assembly furnishing return power comprises the return reach 148 which extends from the point of attachment 132 on the return side of the leverage weight 164, through an opening in the pivot hub 162, to the return-pivot sheave 128 which is so mounted that the center of the pivot reach 146 coincides with the axis of the pivot shaft 161. The return power assembly further comprises the pivot reach 146 which extends from the return-pivot sheave 128 to the downwardly disposed return sheave 127, which is rotatably attached at the other end of the pivot shaft 161, and the vertical return reach 149 therefrom which is attached at its terminus to the return weight 167.

This embodiment is preferred because the long leverarm reach 145 is protected within the lever arm 163. The sheave box 168 is easily removable from its niche within the pivot hub 162 for repair or replacement of the sheaves 125, 128, and the extended pivot shaft 161 permits the transverse reach 143 also to be enclosed and protected by being within the pivot shaft 161. Furthermore, the somewhat awkward plates 65, 66 which are used in the basic embodiment shown in FIG. 1 are dispensed with in this preferred embodiment by means of which there is a minimum of exposed cable to collect lint and possibly to be struck by an operator while tending the machine.

The modification of the preferred embodiment shown in FIGS. 5 and 6 is exactly similar except that the leverage sheave 226 at the far end of the lever arm 263 is journaled on the pin 229 so that the lever-arm reach 245 and the leverage reach 247 pass on either side thereof and are equi-spaced from the opposite interior walls of the lever arm 263. The leverage reach 247 is attached at its terminal end to the attachment point 231 on the outer side of the upwardly projecting tab 228 which is rigidly attached at its bottom edge to the leverage weight 264 and projects upwardly through the slot 268 in the bottom of the lever arm 263.

The return reach 248 is attached at its beginning end to the attachment point 232 on the inner side of the tab 228. The return reach 248 then passes around the horizontally disposed return-pivot sheave 228 within the pivot hub 262 and becomes the pivot reach 246 which coincides with the axis of the pivot shaft 261'. Similarly, the transverse reach 243 coincides with the axis of the pivot shaft 261, passes around the internally mounted and horizontally disposed lever-arm sheave 225, and becomes the lever-arm reach 245 which passes around the leverage sheave 226 at the far end of the lever arm 263.

This modification is the most preferred embodiment because it provides completely enclosed sheave mountings and cable reaches within the lever arm, pivot hub, and pivot shaft of the leverage means. It is especially useful for a dual-lever arm torque-generating mechanism where possibilities of cable interference must be minimized. Where the extended pivot shaft 261 extends as far as the vertical plane passing through the attachment point 101 and transversely to the take-up roll 91, this modification provides very satisfactory cable arrangements in relation to the supporting structure.

It should be understood that a non-rotatable pin which is made of a low-friction material, such as Teflon, is the equivalent of any sheave described hereinbefore in any embodiment of this invention, particularly if the torque-control device measures radius changes of a slowly building roll.

The specific methods and embodiments described hereinbefore are merely for the purpose of illustrating the invention, it being understood that some modification and changes may be made therein without departing from the spirit and principles of the invention. Therefore, the terminology used throughout the specification is for the purpose of description and not limitation, the scope of the invention being defined in the claims.

What is claimed is:

1. Torque control device for a potential-energy torque-generating mechanism, said mechanism comprising a roll adapted to be wound or unwound with flexible material, with said winding and unwinding causing radius changes in said roll, a lever arm pivotally mounted to transmit torque to said roll, and a leverage weight movably mounted on said lever arm, the improvement wherein said torque control device comprises:

A. a distance-measuring means for sensing changes in the radius of said roll,

B. a distance-transmitting means for effecting movement of said leverage weight upon said lever arm in response to changes in said roll radius, and

C. a tension maintaining means including a return weight for maintaining said leverage weight in a position of equilibrium upon said lever arm.

2. The torque-control device of claim 1 in which said distance-measuring means is a rider roll assembly which is pivotably attached to a supporting structure.

3. The torque-control device of claim 1 in which said distance-transmitting means is in the form of a cableand-sheave power assembly comprising a cable system and a sheave system in which one end of said cable system is attached to said distance-measuring means and the other end is attached to said leverage weight.

4. The torque-control device of claim 3 in which said tension-maintaining means is in the form of a cableand-sheave return assembly comprising a cable system and a sheave system in which one end of said cable system is attached to said leverage weight and the other end is attached to said return weight.

5. The torque-control device of claim 4 in which said cable system comprises a lever-arm reach, extending from a lever-arm sheave to a leverage sheave, which is enclosed within said lever arm.

6. The torque-control device of claim 5 in which said cable system comprises a leverage reach, extending from a leverage sheave to the point of attachment on said leverage weight, which is enclosed within said lever arm.

7. The torque-control device of claim 6 in which said cable system in said cable-and-sheave return assembly comprises a return reach which extends from the point of attachment on said leverage weight to a return-pivot sheave and is enclosed within said lever arm.

8. The torque-control device of claim 2 which comprises a ratio-change means.

9. The torque-control device of claim 8 in which said ratio-change means comprises pivotably disposed attachment points on said rider roll assembly and laterally disposed positions for mounting a ratio-change sheave on said supporting structure which are selectively either laterally or vertically disposed or both.

10. The torque-control device of claim 9 in which said ratio-change means comprises chordal-shift, pivotable-shift, and angular-shift attachment arrangements for the terminus of said cable system in said power assembly.

11. The torque-control device of claim 10 in which said chordal-shift attachment arrangement comprises a laterally disposed position for said ratio-change sheave and a selected attachment point which is arcuately aligned therewith.

12. The torque-control device of claim 11 in which said pivotable-shift attachment arrangement comprises a vertically disposed position for said ratio-change sheave and a pivotably-disposed attachment point on said rider roll assembly that is arcuately aligned with said vertically disposed position.

13. The torque-control device of claim 10 in which said angular-shift attachment arrangement comprises a lower position for said ratio-change sheave than said attachment point for the terminus of said cable system.

14. The torque-control device of claim 4 which positions a leverage weight on each lever arm of a duallever arm potential-energy torque-generating mechanism.

15. The torque-control device of claim 14 in which each terminus of said cable systems in each cable-andsheave power assembly is attached to said distance measuring means at the same point through a ratiochange means.

16. The torque-control device of claim 14 in which the lever-arm reach in each cable-and-sheave power assembly is enclosed within the lever arm therefor.

17. The torque-control device of claim 16 in which said sheave system in said power assembly associated with each lever arm comprises a ratio-change sheave, a frame sheave, an axial sheave, a lever-arm sheave, and a leverage sheave.

18. The torque-control device of claim 17 in which said leverage reach and said leverarm reach in each lever arm are on opposite sides of said leverage sheave which is attached to said lever arm at the outer end thereof.

19. The torque-control device of claim 18 in which said return assembly comprises a return-pivot sheave and a return sheave and a pivot reach therebetween, both of said sheaves being so mounted within the pivot hub, to which one end of said lever arm is attached, that the axis of said pivot reach substantially coincides with the axis of said pivot hub.

20. The torque-control device of claim 19 in which said lever-arm sheave has a transverse reach on one side thereof and said lever-arm reach on the other side thereof and is so mounted within said pivot hub that the axis of said transverse reach substantially coincides with the axis of said pivot hub.

21. The torque-control device of claim 20 in which said return-pivot sheave and said lever-arm sheave are attached to a sheave box which is removably inserted into said pivot hub.

22. The torque-control device of claim 21 in which said transverse reach passes over an axial sheave which is so mounted at one end of and within the pivot shaft, to which said pivot hub is rotatably attached, that the axis of said transverse reach coincides with the axis of said pivot shaft.

23. The torque-control device of claim 22 in which said pivot shaft extends substantially to the vertical plane which passes, transversely to said roll, through said end of said cable system where said end is attached to said distance-measuring means.

24. The torque-control device of claim 21 in which said lever arm is slotted and a tab which is attached to the leverage weight protrudes slidably therethrough.

25. The torque-control device of claim 24 in which the terminus of said leverage reach is attached to the outer side of said tab and the terminus of said return reach is attached to the inner side of said tab.

26. The torque-control device of claim 25 in which said lever-arm reach, said leverage reach, and said return reach are enclosed within each lever arm therefor.

27. The torque-control device of claim 1 wherein said return weight may be varied for different types of operation with a greater return weight being provided for unwinding operation and with a lesser return weight being provided for winding operations. 

1. Torque control device for a potential-energy torquegenerating mechanism, said mechanism comprising a roll adapted to be wound or unwound with flexible material, with said winding and unwinding causing radius changes in said roll, a lever arm pivotally mounted to transmit torque to said roll, and a leverage weight movably mounted on said lever arm, the improvement wherein said torque control device comprises: A. a distance-measuring means for sensing changes in the radius of said roll, B. a distance-transmitting means for effecting movement of said leverage weight upon said lever arm in response to changes in said roll radius, and C. a tension maintaining means including a return weight for maintaining said leverage weight in a position of equilibrium upon said lever arm.
 2. The torque-control device of claim 1 in which said distance-measuring means is a rider roll assembly which is pivotably attached to a supporting structure.
 3. The torque-control device of claim 1 in which said distance-transmitting means is in the form of a cable-and-sheave power assembly comprising a cable system and a sheave system in which one end of said cable system is attached to said distance-measuring means and the other end is attached to said leverage weight.
 4. The torque-control device of claim 3 in which said tension-maintaining means is in the form of a cable-and-sheave return assembly comprising a cable system and a sheave system in which one end of said cable system is attached to said leverage weight and the other end is attached to said return weight.
 5. The torque-control device of claim 4 in which said cable system comprises a lever-arm reach, extending from a lever-arm sheave to a leverage sheave, which is enclosed within said lever arm.
 6. The torque-control device of claim 5 in which said cable system comprises a leverage reach, extending from a leverage sheave to the point of attachment on said leverage weight, which is enclosed within said lever arm.
 7. The torque-control device of claim 6 in which said cable system in said cable-and-sheave return assembly comprises a return reach which extends from the point of attachment on said leverage weight to a return-pivot sheave and is enclosed within said lever arm.
 8. The torque-control device of claim 2 which comprises a ratio-change means.
 9. The torque-control device of claim 8 in which said ratio-change means comprises pivotably disposed attachment points on said rider roll assembly and laterally disposed positions for mounting a ratiO-change sheave on said supporting structure which are selectively either laterally or vertically disposed or both.
 10. The torque-control device of claim 9 in which said ratio-change means comprises chordal-shift, pivotable-shift, and angular-shift attachment arrangements for the terminus of said cable system in said power assembly.
 11. The torque-control device of claim 10 in which said chordal-shift attachment arrangement comprises a laterally disposed position for said ratio-change sheave and a selected attachment point which is arcuately aligned therewith.
 12. The torque-control device of claim 11 in which said pivotable-shift attachment arrangement comprises a vertically disposed position for said ratio-change sheave and a pivotably-disposed attachment point on said rider roll assembly that is arcuately aligned with said vertically disposed position.
 13. The torque-control device of claim 10 in which said angular-shift attachment arrangement comprises a lower position for said ratio-change sheave than said attachment point for the terminus of said cable system.
 14. The torque-control device of claim 4 which positions a leverage weight on each lever arm of a dual-lever arm potential-energy torque-generating mechanism.
 15. The torque-control device of claim 14 in which each terminus of said cable systems in each cable-and-sheave power assembly is attached to said distance measuring means at the same point through a ratio-change means.
 16. The torque-control device of claim 14 in which the lever-arm reach in each cable-and-sheave power assembly is enclosed within the lever arm therefor.
 17. The torque-control device of claim 16 in which said sheave system in said power assembly associated with each lever arm comprises a ratio-change sheave, a frame sheave, an axial sheave, a lever-arm sheave, and a leverage sheave.
 18. The torque-control device of claim 17 in which said leverage reach and said lever-arm reach in each lever arm are on opposite sides of said leverage sheave which is attached to said lever arm at the outer end thereof.
 19. The torque-control device of claim 18 in which said return assembly comprises a return-pivot sheave and a return sheave and a pivot reach therebetween, both of said sheaves being so mounted within the pivot hub, to which one end of said lever arm is attached, that the axis of said pivot reach substantially coincides with the axis of said pivot hub.
 20. The torque-control device of claim 19 in which said lever-arm sheave has a transverse reach on one side thereof and said lever-arm reach on the other side thereof and is so mounted within said pivot hub that the axis of said transverse reach substantially coincides with the axis of said pivot hub.
 21. The torque-control device of claim 20 in which said return-pivot sheave and said lever-arm sheave are attached to a sheave box which is removably inserted into said pivot hub.
 22. The torque-control device of claim 21 in which said transverse reach passes over an axial sheave which is so mounted at one end of and within the pivot shaft, to which said pivot hub is rotatably attached, that the axis of said transverse reach coincides with the axis of said pivot shaft.
 23. The torque-control device of claim 22 in which said pivot shaft extends substantially to the vertical plane which passes, transversely to said roll, through said end of said cable system where said end is attached to said distance-measuring means.
 24. The torque-control device of claim 21 in which said lever arm is slotted and a tab which is attached to the leverage weight protrudes slidably therethrough.
 25. The torque-control device of claim 24 in which the terminus of said leverage reach is attached to the outer side of said tab and the terminus of said return reach is attached to the inner side of said tab.
 26. The torque-control device of claim 25 in which said lever-arm reach, said leverage reach, and said return reach are enclosed within each lever arm therefor.
 27. The torque-control device of claim 1 wherein said return weight may be varied for different types of operation with a greater return weight being provided for unwinding operation and with a lesser return weight being provided for winding operations. 